Small controlled fires are used to remove combustibles from a fire’s path. In the open, fires are often steered by winds. Sparks are driven in the direction of prevailing winds spreading fire that way. Fires usually do not double back since in their tracks nothing burnable is left. So they are left to head in the direction they are being blown. Smaller scale fires are more able to be controlled. So far in front of raging wildfire, smaller fires are lit and prevented from spreading in in the direction of prevailing winds. They will however, head slowly against the wind in search of combustibles. As larger fire advances toward the smaller one, air is sucked toward the larger blaze. This creates a small wind current that entices the smaller fire to head toward the larger one . As they meet they help burn each other out.
To aid in carrying out this tactic a network of cleared lanes are laid out in areas susceptible to fires. These lanes are termed fire lanes, fire breaks, or other descriptors that denote a place were fire can be interrupted. These lanes have a duel purpose. They provide access to a wide swath of land in front of an approaching fire. They also give a small lane where nothing much combustible is present. This renders a good place to start small fires and prevent them from crossing the road to the unburnt side. Along these ways, firefighters can easily control fires they light and send off toward the approaching inferno.
I witnessed this tactic being applied on a small island that was being threatened by a rapidly spreading blaze. Penikese Island holds 78 acres and is located 14 miles from mainland Massachusetts. Located in southern Buzzards Bay, it is susceptible to strong ocean breezes. On its premises is a small residential school for adolescent boys. Besides a few small buildings, the island is covered with shrubs and grasslands. In April, the greenery has yet to bloom and still presents last year’s dried growth, a good source of combustibles. That month in 2006, a small fire started on the south west side and rapidly built into an uncontrollable inferno. Breezes were driving it in a Northeasterly direction. Luckily, a small pathway bisects the island from north to south. The fire was several hundred yards from this break. Some staff and a few students headed up the path lighting small fires on the western side of the lane.
At each fire, someone was left with a shovel to beat down any flames that threatened to cross the road. These small fires were only allowed to head against the wind in a westerly direction. Slowly they proceeded that way. As the wildfire closed in, the smaller blazes hurried to meet it. Finally it consumed itself and the island residents celebrated the sparing of their structures, all located to the east of the fire lane. Until new growth sprouted anyone approaching Penikese would witness it half blackened, neatly divided by the firebreak.